Fix links to Cabal User Guide

Author: mpilgrem

doc/faq.md

@@ -412,7 +412,7 @@
     is as follows:
 
     * In the Cabal file, the following
-      [`ld-options`](https://cabal.readthedocs.io/en/stable/cabal-package.html#pkg-field-ld-options)
+      [`ld-options`](https://cabal.readthedocs.io/en/stable/cabal-package-description-file.html#pkg-field-ld-options)
       are set: `-static` and `-pthread`.
 
     * The Stack command is run in a Docker container based on Alpine Linux. The

doc/tutorial/hello_world_example.md

@@ -387,7 +387,7 @@ functionality to create a Cabal file.
     those components depend.
 
     The
-    [Cabal User Guide](https://cabal.readthedocs.io/en/stable/cabal-package.html)
+    [Cabal User Guide](https://cabal.readthedocs.io/en/stable/cabal-package-description-file.html)
     is the definitive reference for the Cabal package description format.
 
     The [Hpack](https://github.com/sol/hpack#quick-reference) documentation